The present invention generally relates to computer-aided troubleshooting systems and, more particularly, to computer-aided troubleshooting systems for auxiliary power units (APU).
APUs are used on a vast number of commercial and military vehicles, such as aircraft, tanks, and other ground vehicles. Their function, in general, is to provide electrical power to operate the vehicle""s electronic systems at a significantly lower fuel consumption then when the main engine is used. Other APU functions include charging the batteries, operating the hydraulic system, and providing the compressed air. The APU Electronic Control Unit (ECU) controls the turbine engine by providing the control signals necessary to operate engine servos, valves and relays. The ECU also monitors engine operation using signals from several sensors mounted in the engine.
The air-worthiness of aircraft is dependent upon proper functioning of many interdependent aircraft components. The APUs are typically reliable but are subject to failure. An aircraft cannot take off if the APU is not functioning properly. Most often, to determine the cause of a failure of an APU, maintenance personnel use standard electronic test equipment, such as voltmeters, ohmmeters and oscilloscopes.
There is an increasing need for automated troubleshooting systems, which has prompted many companies to turn to application software to deploy and manage their troubleshooting applications effectively. Quite commonly, these applications are configured to interface with a tested unit in real time, in order to explore, evaluate and implement a corrective action as soon as possible.
Unfortunately, presently there is no existing computer-aided troubleshooting software, loadable in a conventional portable personal computer, that allows customer field service personnel to retrieve the internal information from the unit under test, such as an aircraft APU ECU, in order to facilitate troubleshooting of the malfunctioning unit, which is also capable of controlling the tested unit.
Currently, troubleshooting software applications must be developed to work within a custom designed hardware environment. As a result, application developers frequently find that they have little or no control over which product is to be used to support their applications or how the database is to be designed. In some cases, developers may even find that data critical to their application have to be hard-coded and cannot be dynamically updated. Thus, the developer is forced to turn to more complex (and potentially cumbersome) alternatives to gain access to needed data sources. Often, the alternatives are more costly and time-consuming to implement, require a more sophisticated set of skills to implement, and may consume additional machine resources to execute.
Some presently available troubleshooting software application programs depend on hard coding of previously known unit under test parameter addresses, where data items are stored as results of previously executed program instructions, and are not retrieved from the unit under test during the troubleshooting session. Therefore, the software application program must be modified in order to access different data. Some other software application programs cannot dynamically calculate the necessary data locations, thus preventing the application program from being useable in more than a singular application. Furthermore, if a modification in a software application program is made, it is possible that the wrong data would be accessed after the modification.
Therefore, there is a need for a method and a reusable software module, loadable in a conventional personal computer, which can interface with a tested Auxiliary Power Unit Electronic Control Unit, to provide persistent troubleshooting data, and to facilitate troubleshooting and control of malfunctioning units. This would simplify the design, development, and maintenance of troubleshooting applications and provide applications with a function that would otherwise be inaccessible.
One aspect of the present invention is an engine monitoring and control system. The system includes a tested unit having a symbol table with addresses of monitored and controlled parameters, an external portable personal computer having a memory, a display and a graphical user interface (GUI) responsive to user commands, and a communication link between the tested unit and the personal computer. The GUI is used for creating customized set of application-specific GUI display pages with icons and text, for displaying received parameter values, and for selecting commands and parameters from the displayed pages. The computer executes a monitoring software program including a set of computer-executable program instructions for retrieving the tested unit parameter values and controlling the tested unit performance. The memory receives the symbol address table before the test and the monitoring software program dynamically updates the symbol addresses into a global arrays table during the test, by recalculating necessary data locations, if needed. The tested unit is preferably an Auxiliary Power Unit (APU) Electronic Control Unit (ECU). The monitoring software program may be remotely controlled by a remote control system for off-site monitoring and control.
Another aspect of the present invention is a method implemented in the above-mentioned system embodiment of the present invention.